An Optimal Observable for Color Singlet Identification

TL;DR

This paper introduces the 'jet color ring', an optimal observable for identifying color singlet decays in jets, outperforming existing methods in simulations of boosted Higgs and electroweak boson decays.

Contribution

The paper proposes a new, theoretically optimal color tagger based on matrix element ratios, improving discrimination of color singlet decays in jet substructure analysis.

Findings

Jet color ring outperforms other observables in simulations.

The observable is theoretically optimal within the soft limit approximation.

Effective in distinguishing boosted Higgs and electroweak boson decays.

Abstract

We present a novel approach to construct a color tagger, i.e. an observable that is able to discriminate the decay of a color-singlet into two jets from a two-jet background in a different color configuration. We do this by explicitly taking the ratio of the corresponding leading-order matrix elements in the soft limit, thus obtaining an observable that is provably optimal within our approximation. We call this observable the "jet color ring" and we compare its performance to other color-sensitive observables such as jet pull and dipolarity. We also assess the performance of the jet color ring in simulations by applying it to the case of the hadronic decays of a boosted Higgs boson and of an electroweak boson.